21024645 has 32 divisors (see below), whose sum is σ = 35424000. Its totient is φ = 10627584.

The previous prime is 21024643. The next prime is 21024743. The reversal of 21024645 is 54642012.

It is not a de Polignac number, because 21024645 - 2¹ = 21024643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51201 + ... + 51609.

It is an arithmetic number, because the mean of its divisors is an integer number (1107000).

Almost surely, 2^21024645 is an apocalyptic number.

It is an amenable number.

21024645 is a deficient number, since it is larger than the sum of its proper divisors (14399355).

21024645 is a wasteful number, since it uses less digits than its factorization.

21024645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21024645 is about 4585.2638964404. The cubic root of 21024645 is about 276.0003019320. Note that the first 3 decimals are identical.

Adding to 21024645 its reverse (54642012), we get a palindrome (75666657).

The spelling of 21024645 in words is "twenty-one million, twenty-four thousand, six hundred forty-five".